With people's increasing concern about global warming, environmental pollution and energy crisis, sustainable energy strategies have been effectively explored. Hydrogen is gaining momentum as an alternative to traditional fossil fuels. Among them, hydrogen production by acid water electrolysis is known for its high efficiency and high selectivity (up to 99.).995%) and pollution-free. However, at high current densities (more than 500 mA cm-2 or 1000 mA cm-2), there is an urgent need for efficient and stable electrocatalysts to improve the slow kinetics of water splitting. However, the preparation of micro-nano catalysts has encountered various obstacles, such as high surface tension, particle agglomeration, poor activity and stability, complex preparation, low production efficiency, high cost and limited intrinsic structure, which further hinder the development of acid water electrolysis technology.
Recently,Yanan Chen, Tianjin Universitywithliu yanchangand ultrafine high-entropy alloy (HEA) nanoparticles were synthesized by high-temperature liquid-phase impact (HTLS). Among them, the average particle size of PTConiruir HEA-NPS is only 324 nm and uniformly dispersed on the carbon black support, exhibiting abundant lattice strain. In a typical solid-state high-temperature impingement method, the heating and cooling rate can reach about 105 K s1 with a peak temperature of 3000 K. While these parameters can be adjusted to some extent, environmental factors such as pressure, atmosphere, cappers and reducing agents remain relatively fixed. In contrast, the liquid phase method provides more tunable parameters such as capping agents, solvents, dispersants, etc. In addition, the presence of a liquid-phase environment promotes a more homogeneous reaction process and easier morphological and phase controlled end products. Importantly, the morphology, size, size and crystalline phase of HEA-NPS are adjusted by incorporating liquid media and introducing reducing agents and capping agents; In addition, the utilization of Joule heating facilitates the maintenance of high-temperature reactions and enables defect engineering of HEA-NPS.
Based on the above advantages, this strategy enables the preparation of efficient catalysts with fine dimensions, unique atomic arrangements, and defects. These catalysts exhibit an abundance of non-coordination sites and dangling bonds, which will contribute to their excellent performance. Therefore, the obtained PTConiruir HEA-NPS has excellent activity and stability against hydrogen evolution reaction (HER), with overpotentials of only 18 and 408 mV at 10 mA cm-2 and 1 A cm-2 current densities, respectively. In addition, these HEA-NPS are at 0The excellent activity of 5 M H2SO4 after 10000 CV cycles further highlighted their superior stability to HER. Overall, this work provides a new avenue for further advancing the high-throughput synthesis of phased, ultra-fine size, defect- and strain-rich, and avoidance of aggregation and phase separation of HEA-NPs.
rapid high-temperature liquid shock synthesis of high-entropy alloys for hydrogen evolution reaction. acs nano, 2024. doi: 10.1021/acsnano.3c07703